The speech and noise are then summed at different SNRs [1]}, to create various levels of noise scenarios.
The SNR is defined as the ratio of active speech energy compared to the constant noise energy.
Active speech energy is determined using the ITU-T P.56 recommendation [2]}.
The noise energy is the root mean square value across the whole noise segment.
According to the measured energy of speech and noise, the noise is scaled appropriately to obtain four SNR levels (-5;0;10;20) before summing the clean speech and noise.
